Bolivian Mummy Reveals Earliest Evidence of Strep Throat in the Americas

A 700-year-old mummy from Bolivia has yielded the earliest confirmed evidence of group A Streptococcus bacteria in the Americas, offering new insights into the historical presence of pathogens that cause strep throat and scarlet fever long before European contact.

The discovery, made through dental pulp analysis of a child’s molar from the Andes region, pushes back the known timeline of Streptococcus pyogenes in the Western Hemisphere by several centuries. Previously, the oldest molecular evidence of this bacterium in the Americas dated to colonial-era remains, suggesting it may have been introduced by Europeans. This finding challenges that assumption, indicating the pathogen was already circulating among Indigenous populations well before the 16th century.

Researchers from institutions in Bolivia, the United States, and Europe identified bacterial DNA fragments in the tooth’s pulp chamber using advanced paleogenetic techniques. The genetic sequences matched modern strains of group A Streptococcus, specifically those associated with pharyngitis and the potential to trigger scarlet fever under certain conditions. The child, estimated to have been between 6 and 8 years old at death, showed no overt skeletal signs of systemic infection, suggesting the illness may have been acute or resolved shortly before death.

Scarlet fever, a condition that can follow untreated strep throat, is characterized by a distinctive rash, fever, and sore throat. While treatable with antibiotics today, it was a significant cause of morbidity and mortality in children during the 19th and early 20th centuries. Understanding its deeper historical roots helps scientists trace the evolution and global spread of bacterial pathogens, particularly how human migration, population density, and ecological changes influenced disease transmission over time.

Dr. María Constanza Ceruti, a bioarchaeologist involved in the study, noted that the presence of the bacterium in a high-altitude Andean context suggests complex pathways of disease ecology in pre-Columbian societies. “We often assume that epidemic diseases arrived with colonization, but this shows some pathogens were already part of the human experience in the Americas,” she said in a statement released with the study. “It doesn’t mean outbreaks were common, but it confirms the bacterium had opportunities to circulate, adapt, and persist in isolated communities.”

The findings also contribute to ongoing debates about the peopling of the Americas and the timing of pathogen introduction. While some researchers have proposed that certain infectious diseases were absent in the pre-Columbian New World, this discovery adds to growing evidence that a range of bacteria and viruses were present, albeit possibly at low prevalence or in limited geographic pockets.

Experts caution that detecting ancient pathogen DNA does not equate to documenting widespread epidemics. The mummy represents a single case, and without additional cases from the same time period and region, it is difficult to assess the true burden of streptococcal disease in ancient populations. However, the molecular confirmation provides a critical benchmark for future studies aiming to reconstruct the historical epidemiology of infectious diseases in the Americas.

The research team emphasized the importance of ethical collaboration with descendant communities when conducting such studies. The mummy was recovered from a site near Lake Titicaca, an area with deep cultural significance to Indigenous Aymara and Quechua peoples. Researchers worked with local heritage authorities to ensure the analysis respected cultural protocols while advancing scientific understanding.

Moving forward, scientists plan to screen other ancient remains from similar contexts to determine whether group A Streptococcus was more widespread than this single finding suggests. Advances in metagenomic sequencing and improved preservation techniques are making it increasingly possible to detect faint microbial signals in archaeological specimens, opening a new window into the deep history of human disease.

This discovery underscores that the story of human health is not only shaped by modern medicine but also by millennia of co-evolution with microbes. By studying ancient infections, researchers gain perspective on how pathogens emerge, adapt, and persist — knowledge that can inform modern efforts to anticipate and manage infectious disease threats.